Motor speed control for use with automatic clutches



Oct. 16, 1956 R. BINDER 2,766,862

MOTOR SPEED CONTROL FOR USE WITH AUTOMATIC CLUTCHES Filed March 4, 1955 GEAR SHIFT LEVER 27 35 63 54 22 s r 7 Z4 SWITCHCONTACTS i9 CbOSED DURING GEAR smrrme i llurcn DISENGAGING LEVER 18 i I V & L

12 J0 CENTRIFUGAL 28 CLUTCH Pl k 30 y F762 1 I 27 -34 I x: I a 42 642 9 57 much/r01 Fla-Mao BIA/05a MUTOR SPEED CGNTRGL FOR USE WITH AUTOP/lATllC CLUTCI'ES Richard Binder, Schweinfurt am it ain, Germany, assignor to Fichtel & Sachs A. G., Schweinfurt am Main, Germany, a corporation of Germany Application 1 arch 4, 1955, Serial No. 492,153

6 Claims. (Cl. 192-.08)

The present invention relates to an engine speed control device for use with automatic clutches, the speed control device being arranged to maintain the engine speed sufficiently high to assure smooth reengagement of the clutch after its disengagement during gear shifting.

An automatic clutch control system of the type with which the present invention is suitable for use is described in the pending application of Richard Binder, Serial No. 466,410 filed November 2, 1954.

The invention contemplates the use of a clutch which automatically becomes engaged whenever the engine speed exceeds a predetermined minimum value. During gear shifting, a power actuated device disengages the clutch when it would otherwise be engaged and thereafter allows it to reengage smoothly after the gear shifting has been completed. Usually, the power actuated disengaging device is controlled by an electric circuit including a switch associated with the gear shift lever. The clutch may be of the centrifugal type, a speed-controlled electro-magnetic clutch controlled by the generator voltage, for instance, or the clutch may be operated by a servomotor of the fluid pressure type such as a vacuum, compressed air or hydraulic device, or may comprise an engaging and disengaging device operated by an electric motor.

The use of an automatic clutch of this type makes the use of a clutch pedal unnecessary. However, if the engine speed is permitted to drop during gear shifting, the clutch will disengage not only by operation of the power actuated disengaging device but also due to the speed reduction of the engine. Reengagement will then tend to be jerky, particularly when shifting back from a higher gear to lower gear. When driving on icy or slippery pavements, this ac tion may be hazardous, tending to throw the vehicle into a skid.

The present invention comprises a speed control device which maintains the engine speed high enough so that the clutch will be disengaged only by operation of the power actuated disengaging device and not by the speed-control disengaging device during the shifting of gears. A smooth reengagement of the clutch by the power actuated disengaging device is therefore assured without any possibility of interference from the speed-controlled disengaging device. Conveniently, the minimum speed control device may act on the engine throttle to prevent the engine from dropping to idling speed.

Various objects, features and advantages of the invention will become apparent upon reading the following specification together with the accompanying drawing forming a part hereof.

Referring to the drawing:

Figure 1 is a diagrammatic elevational view showing an illustrative embodiment of the invention.

Figure 2 is an enlarged elevational View of a minimum speed control device shown partly in section, the device being shown in its operated position preventing the engine from dropping to idling speed.

Figure 3 is a view similar to Fig. 2 showing the minimum speed control device in its inoperative position in which position it has no effect upon the engine speed.

Figure 4 is a schematic circuit diagram illustrating the electrical connections between the speed control device and electrical control contacts which are included in a switch actuated by the gear shift lever while shifting from one gear ratio to another.

Referring to Fig. 1, the invention is shown applied to a motor vehicle of which only those portions which are directly concerned with the present invention are shown. An internal combustion engine designated generally as 10 is connected through a centrifugal clutch 11 and a transmission 12 to an automative drive or propeller shaft 13 which extends rearwardly to a difierential or other driving mechanism (not shown). The connection to the differential includes the usual universal joint 14. The centrifugal clutch 11 may be of the type shown in the application of Richard Binder, Serial No. 466,410 filed November 2, 1954, (Figs. 2 and 3) or it may take any other desired form in which the clutch becomes engaged whenever the engine speed exceeds a predetermined minimum speed, but the clutch will always be disengaged whenever the engine speed drops below this predetermined mmimum speed, for instance to idling speed. A master clutch disengaging lever 15 forms a part of the clutch 11 and when rotated in a counterclockwise direction as viewed in Fig. l, the lever 15 will always disengage clutch 11 even though the engine speed may be considerably higher than the predetermined minimum clutch engaging speed.

A vacuum operated cylinder 17 is mounted on one side of engine 1% Vacuum cylinder 17 actuates a pull rod 18 which is pivotally connected by a coupling 19 to the upper free end of master clutch control lever 15. A turnbuckle type of coupling 20 is included in pull rod 18 to permit adjustment of the action of vacuum cylinder 17 with respect to clutch 11.

A suction line 22 connects the vacuum cylinder 17 to an electrically actuated control valve 23. A further suction line 24 connects the control valve 23 with the intake manifold 25 of the engine '10.

The intake manifold 25 is supplied with a combustible air-fuel mixture from a carburetor 27 through a supply duct 28. The supply duct 28 has a butterfly throttle valve member 22 disposed therein, the throttle valve member 29 being carried by a throttle shaft 30 for rotation therewith to control and vary the speed of engine 10. The throttle shaft 30 has a special control arm 32 mounted thereon, the usual accelerator pedal controlled arm being omitted from the drawing for simplicity of illustration.

The free end of control arm 32 carries an adjustment screw 33. The lower end of adjustment screw 33 is engageable with the free left hand end 34 of a minimum speed control lever 35 mounted on the body of the control valve 23. The speed control lever 35 is pivoted intermediate its ends on a pivot pin 37 supported by a pedestal 38 mounted on the body of control valve 23. The right hand end of speed control lever 35 is pivotally connected at 39 to be controlled by a flexible diaphragm 40 through a link member 42 which is yieldingly urged upwardly by a helical compression spring 43. The diaphragm 40 is peripherally secured to the body of control valve 23 by a centrally apertured cover plate 44 which limits the upward movement of diaphragm 49 while permitting link member 42 to pass freely therethrough. The diaphragm 40 thus defines in part a vacuum chamber 45 which communicates through a metering orifice 47 with a valve chamber 48 with which the suction line 22 is in continuous communication. A suction passage as is connected by suction line 24 with intake manifold 25, and while engine 10 is running, passage 49 will ordinarily be under suction from intake manifold 25.

5. In combination with an internal combustion engine having an intake manifold; throttle means connected with said intake manifold for controlling the speed of said engine; a transmission; gear shifting means for selecting a desired gear ratio within said transmission; a clutch selectively engageably and disengageably connecting said engine to said transmission; means responsive to the speed of said engine for causing engagement of said clutch whenever said engine speed exceeds said predetermined minimum speed; and suction operated means connected with said clutch for causing disengagement thereof during times when said engine speed exceeds said predetermined minimum speed; the provision of suction operated minimum speed control means acting on said throttle means to maintain said engine speed at a speed higher than said predetermined minimum speed; electrically actuated valve means controlled by said gear shifting means; and a suction line extending from said intake manifotd to said valve means, said valve means connecting said suction line to both of said suction operated means during shifting actuation of said gear shifting means for simultaneously disengaging said clutch and maintaining the speed of said engine higher than said minimum speed during said shifting actuation of said gear shifting means.

6. The combination according to claim 5, further comprising air fiow rate regulating means interposed between the atmosphere and said valve means for delaying the restoration of atmospheric pressure to both of said suc tion operated means.

References Cited in the file of this patent UNITED STATES PATENTS 2,568,958 Hey et al Sept. 25, 1951 2,622,711 Charnbonneau Dec. 23, 1952 2,695,088 Bradbury Nov. 23, 1954 

